Your resistance to arcane magic comes at a price. When an arcane spell does penetrate you spell resistance, it is deadlier than normal.
Prerequisites: No Friend to the Arcane
Penalty: Whenever you take damage from an arcane spell, add one point of damage per die. If an arcane spell effects you but does not deal damage, its effects last one more or one less round per caster level (whichever is worse for you).